James M. Cheverud

RESEARCH INTERESTS

My research focuses on evolutionary genetics, morphology, the genetics of complex traits and diseases in model organisms, and primate and mammalian evolution. Our studies of complex traits have been performed in non-human primates and in mice, as a model organism. We have studied a variety of traits, including cranial and skeletal morphology, obesity, diabetes, growth, brain morphology, congenital heart disease, scarless wound healing, arthritis, osteoporosis, and knee cartilage regeneration. In these studies we have documented that the effects of genes depend critically on their context, such as environment (high fat diet), sex, and alleles at other loci (epistasis). In general, genes do not have effects on their own but only in a complex web of specific genetic and environmental contexts. This work also aims to identify the genetic elements and nucleotide changes responsible for complex trait variation.

Since gene effects vary depending on context, these effects are genetically variable and will evolve. In a number of studies in mice and opossums, we have shown that the effects of genes on single traits and on a range of multiple traits (pleiotropy) are genetically variable. We have shown that directional natural selection will result in the evolution of gene effects to increase variation along the selected dimension, thereby accelerating adaptation.

We have also been involved in many studies of systematics and evolution in non-human primates and in human evolution. In these studies we have shown that complex phenotypes tend to be modular with functionally and developmentally traits sharing their underlying genetic bases (morphological evolution) and that patterns of heritable variation can prove critical in either constraining or facilitating adaptation. We have used modern evolutionary quantitative genetic models to examine the historical forces, genetic drift and natural selection, responsible for the observed morphological diversification of primates, with special emphasis on the New World Monkeys.